Internal-combustion engine exhaust system



Aug. 29, 1944.

L. E. MULLER INTERNAL COMBUSTION ENGINE EXHAUST SYSTEM Filed Oct. 15,1941 Bnnentor Q 5 [Zcya'i 6. WfzzZZaf/ My (Itfomegs Patented Aug. 29,1944 INTERNAL-COMBUSTION ENGINE EXHAUST SYSTEM Lloyd E. Muller, Flint,Mlch., assignor to General Detroit, Mlcln, a corpora- MotorsCorporation,

tion of Delaware Application October 15, 1941, Serial No. 414,986

9 Claims.

It is the general practice to provide multicylinder internal combustionengines with exhaust systems which include a manifold into which theexhaust gases from the several cylinders of the engine are dischargedand an exhaust pipe, silencer and tail pipe through which the exhaustgases pass successively from the manifold to the atmosphere. Theresistance ofiered by the exhaust system to the passage of the exhaustgases creates back pressure which interferes with the discharge of theexhaust gases from the cylinders and prevents the engine developing thepower which it would be capable of developing without the exhaustsystem.

The situation can, of course, be alleviated by increasing the size ofthe elements of the exhaust system or providing a separate exhaustsystem for each cylinder or for each of different groups of cylinders ofthe engine but these expedients are, of course, expensive and requirespace, particularly for the silencers, which may not be available,especially in modern automotive vehicles to which my invention isparticularly applicable, and also, in the case of the expedient firstmentioned, may reduce the silencing capacity of the exhaust system.

My invention resides in an exhaust system for an internal combustionengine, including a silencer, which makes it possible to decrease theresistance olTered by the exhaust system of the engine to the passage ofthe exhaust gases and increase the power the engine can develop withoutthe employment of more than one silencer or increasing prohibitively, ifat all, the size of the elements or reducing the silencing capacity ofthe exhaust system. I

For a better understanding of the nature and objects of this inventionreference is made to the following specification and the accompanyingdrawing in which the preferred embodiment of the invention is describedand illustrated.

In the accompanying drawimg:

Figure 1 is a side elevation of the propelling engine and associatedparts of an automotive vehicle equipped with an exhaust system inaccordance with my invention.

Figure 2 is an enlarged lengthwise section, taken on the line 22 ofFigure 3, through the exhaust silencer of the engine shown in Figure 1.

Figure 3 is an enlarged section through the silencer taken on the line3-3 of Figure 1.

Figure 4 is a further enlarged fragmentary cross section through one ofthe exhaust gas tubes of the silencer.

In the drawing, the reference character I indicates a straight eight"internal combustion engine and the reference character II the exhaustsilencer of the engine.

The exhaust silencer ll includes a shell l2 which is roughly ellipticalin cross section and a shell l3 which is approximately circular in crosssection. The ends of the shell I! are closed by heads .M and the ends ofthe shell l3 by heads l5. lengthwise by a partition I6 whose outer edgeis secured circumferentially to the shell. The shells l2 and I3 aredisposed end to end with the axis of the shell IS in the plane of themajor axis but to one side of the intersection of the major with theminor axis of the shell l2.

Through the shells I2 and I3, their heads I4 and I5 and the partition I6in the shell l3 extend two exhaust gas tubes I! which are spacedlaterally from each other and the shells and secured in openings in theheads of the shells.

,Within the shell l2 the tubes II are encircled by a shell l8 which isroughly elliptical in cross section and'spaced from the tubes and theshell [2. The shell I8 is secured to and extends from one head of theshell I! to a point near but at a distance from the other head. Througheach of the tubes l'l within the shell l2 and within the confines of theshell l8 extend four groups of perforations l9. Through theseperforations and the space between the shell l8 and the tubes and thespace between the end of th shell l8 and the head of the shell l2 itterminates short of the chamber 20 defined by the shell l2, its heads I4and the shell [8 communicates as a side branch with the tubes l1.Through the tubes l1 within the shell l3 on each side of the partitionI6 extends another group of perforations l9 through which the chambers2| defined by the shell l3, its heads I5 and the partition 16communicate as side branches with the tubes ll.

Instead of a single manifold into which the exhaust gases from all ofits cylinders are discharged, the engine I 0 is equipped with twoexhaust manifolds 22 and 23 which are connected, respectively, to theexhaust ports of the front four and the exhaust ports of the rear fourcylinders of the engine. The exhaust silencer II is installed on theengine ID with one end of one of its exhaust gas tubes ll connected tothe exhaust manifold 22 by an exhaust pipe 24 and the corresponding endof the other of its exhaust gas tubes l1 connected to the exhaustmanifold 23 by an exhaust pipe 25. To the other end of each of theexhaust gas tubes I1 is connected a tail pipe 26.

The interior of the shell I3 is subdivided.

When the engine i is operating the exhaust gases from its front fourcylinders are discharged into the manifold 22 and the exhaust gases fromits rear four cylinders discharged into the exhaust manifold 23. Fromeach of the manifolds 12 and 23, the exhaust gases pass into the exhaustpipe connected to that manifold, the exhaust gas tube ll of the silencerto which that exhaust pipe is connected and the tail pipe 28 which isconnected to that exhaust gas tube and, thence, to the atmosphere. Thechamber 20 and the perforations I and spaces through which itcommunicates with the exhaust gas tubes l1 and the chambers 2i and theperforations I! through which they communicate with the exhaust gastubes, of course, constitute resonators which are preferably so tuned asset iorth in the Wilson Patent No. 2,323,955, dated July 13, 1943, thatthey will resonateto and thus attenuate sound waves to which the exhaustnoise of the engine is attributable. Sound waves which may pass from oneof the exhaust gas tubes II to the other will also, of course, beattenuated in the course of their passage through the perforations i9and the intervening space and will also be attenuated by and attenuateby interference the sound waves in the exhaust gas tube into which theypass.

Because in the exhaust system herein disclosed the exhaust gasesdischarged from some and the exhaust gases discharged from others of thecylinders of the engine are conducted from the cylinders to theatmosphere by separate ducts, less back pressure will be developed inthis exhaust system than in an exhaust system, with an exhaust gas ductand a silencer of comparable size, of the type generally provided onmulticylinder internal combustion engines. Consequently, an engineequipped with the exhaust system herein disclosed will develop morepower than an engine equipped with an exhaust system, with an exhaustgas duct and a silencer of comparable size, of the type generallyprovided on multicylinder internal combustion engines. The invention,therefore, makes it possible to decrease the resistance offered by theexhaust system of an engine to the passage of exhaust gases and increasethe power the engine can develop without the employment of more than onesilencer or increasing prohibitively, ii at all, the size of theelements or reducing the silencing capacity of the exhaust system.

It will, I think, be clear from what has been said that the inventionherein disclosed is applicable to the intake as well as the exhaustsystems of internal combustion engines.

I claim:

1. In an internal combustion engine with more than three cylinders, asilencer which includes a plurality of ducts of which each is connectedto the exhaust ports of a plurality of the cylinders, a shell whichencircles the ducts and with them defines a compartment, a partitionwhich subdivides the compartment into chambers of which eachcommunicates as a side branch with a plurality of the ducts and whichconstitute elements of resonators which are so tuned that they resonateto and thus attenuate sound waves which contribute to the exhaust noiseof the engine.

2. In an internal combustion engine with more than three cylinders, asilencer which includes a plurality of ducts of which each is connectedto the corresponding ports of a plurality of cylinders, and a shellwhich encircles the ducts and with them defines a chamber whichcommunicates with the ducts as a side branch and constitutes an elementof a resonator which is so tuned that it resonates to and thusattenuates sound waves which contribute to the noise or the engine whichissues from. the mentioned ports.

3. In an internal combustion engine with a plurality of cylinders, asilencer which includes a plurality of ducts of which each is connectedto the exhaust ports of a plurality of the cylinders, and a chamber withwhich a plurality of the ducts communicate between their ends.

4. In an internal combustion engine with more than one cylinder, asilencer which includes a plurality of ducts of which one is connectedto a port of one and the other to the corresponding port of another ofthe cylinders, and a shell which encircles the ducts and with themdefines a chamber which communicates with the ducts as a side branch andconstitutes an element of a resonator which is so tuned that itresonates to and thus attenuates sound waves which contribute to thenoise of the engine which issues from the mentioned ports.

5. In an internal combustion engine with a plurality of cylinders, asilencer which includes a plurality of ducts of which one is connectedto a port of one and the other to the corresponding port of another ofthe cylinders, and a chambe: which communicates with a plurality of theducts as a side branch and constitutes an element of a resonator whichis so tuned that it resonates to and thus attenuates sound waves whichcontribute to the noise of the engine which issues from the mentionedports.

6. In an internal combustion engine with a plurality of cylinders, asilencer which includes a plurality of ducts of which one is connectedto a port of one and the other to the corresponding port of another ofthe cylinders and a chamber with which a plurality of the ductscommunicate between their ends.

'7. In an internal combustion engine with a plurality of cylinders, asilencer which includes a plurality of ducts of which one is connectedto a port of one and the other to the corresponding port of another ofthe cylinders, and a plurality of chambers with each of which aplurality of the ducts communicate between their ends.

8. In an internal combustion engine with a plurality of cylinders, asilencer which includes a plurality of ducts of which each is connectedto the exhaust ports of a plurality of the cylinders, and a plurality ofchambers with each of which a plurality 0f the ducts communicate betweentheir ends.

9. In an internal combustion engine with a plurality of cylinders, asilencer which includes a plurality of ducts of which each is connectedto the exhaust ports of a plurality of the cylinders, and a plurality ofchambers of which each communicates as a side branch with a plurality ofthe ducts and which constitute elements of resonators which are so tunedthat they resonate to and thus attenuate sound waves which contribute tothe exhaust noise of the engine.

LLOYD E. MUILER.

